The goal of this network is to bring together basic and clinical scientists conducting work in areas relevant to psychological aspects of sexual differentiation, to build an integrated and interdisciplinary understanding of the topic, focusing on both normal developmental processes and developmental problems. This should also lead to an understanding of the complex origins of the psychological problems associated with variations in psychosexual differentiation, including those common in children and adolescents with intersex disorders and those with sex-atypical behavior, and ultimately to evidence-based treatments specific to these populations. The aims are to (1) strengthen conceptual and empirical linkages among research in several areas: (a) physical and behavioral sexual differentiation; (b) relation of psychosexual differentiation to psychopathology; (c) child, family, and peer influences on the development of mental health and illness in children and adolescents with prenatal risk factors or chronic health conditions; (2) develop collaborative research programs designed to describe (a) processes through which genes, prenatal sex hormones, and postnatal social experiences jointly contribute to the development of psychosexual differentiation; (b) ways in which trajectories of psychosexual differentiation affect overall psychological development; (c) ways in which mental health of children and adolescents with intersex conditions or sex-atypical behavior is influenced by non-sex-typed physical and social characteristics; and to (d) develop or refine animal paradigms to explain biological and social processes underlying normal and nonnormative sex-typed behaviors. Network activities include full and targeted subgroup meetings, electronic collaboration, visits between labs, development and implementation of pilot projects, and development of collaborative multi-site grant applications. The 15 network members represent expertise from molecular through behavioral levels, with rodent, monkey, and human child, adolescent, and adult populations: Sheri Berenbaum (PI), David Sandberg, Adrian Angold, Dennis Drotar, Rina Das Eiden, Erica Eugster, Barry Kogan, Mary Lee, Peter Lee, Carol Martin, Cindy Meston, Emile Rissman, Sally Shaywitz, Eric Vilain, and Kim Wallen. Consultants participating in discussion of specific issues include Robert Blizzard, Norman Fost, David Page, John McArdle, Ora Pescovitz, and Susan Resnick.